Kawa no Nushi Tsuri

Kawa no Nushi Tsuri is a RPG based on fishing. You play as a young man whose sister is really ill. You gotta catch this big-arse fish called the River King to cure her. So, you do the only logical thing: travel from fishing hole to fishing hole trying to get the River King. Unfortunately, this River King is pretty popular, because all sorts of animals attack you while you travel.